All is not well between Facebook CEO Mark Zuckerberg and co-founders of platforms like Instagram and WhatsApp.

Instagram co-founders Kevin Systrom and Mike Krieger announced early this week that they are leaving the company they co-founded nearly eight years ago. The duo announced that they are leaving Facebook, which bought the photo-sharing platform for around $1 billion six years ago. The exit comes just months after WhatsApp co-founder Jan Koum decided to leave Facebook.

Since the official confirmation from Systrom, there have been multiple reports detailing the reason for their exit. According to New York Times, Instagram co-founders decided to leave Facebook (thus Instagram) after growing “disagreements over tweaks to their product, staffing changes and how over the last year [Mark] Zuckerberg asserted more control over their business.” The reason does not really seem new and it is precisely the reason why Koum decided to leave WhatsApp.

WhatsApp was acquired by Facebook more than four years ago for a record $19 billion. Some reports claim that Facebook paid as much as $22 billion after regulatory clearances for the deal. Ten months ago, Acton left Facebook to focus on a nonprofit and his exit did not really gather as much attention as that of Koum or Instagram co-founders. In an exclusive interview with Forbes, Acton reveals why he left Facebook and his support for the ongoing #DeleteFacebook movement.

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Since his exit, Acton has been the most vocal supporter of stronger encryption for services such as WhatsApp. He claims the decision to leave Facebook claim after its leaders, CEO Mark Zuckerberg and COO Sheryl Sandberg, began questioning the encryption algorithm he built, in order to monetize the messaging platform.

While Koum left after all of his stocks vested and made him a young billionaire, Acton left even before his final portion of stock grants vested. “It was like, okay, well, you want to do these things I don’t want to do. It’s better if I get out of your way. And I did,” Acton explains the reason behind him leaving Facebook. His decision to leave Facebook before the final tranche of stocks vested is estimated to have cost him around $850 million.

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In the interview, Acton also reveals how he proposed a metered monetization model and Sheryl Sandberg shot down the idea. He claims that Facebook wanted to show targeted ads to WhatsApp users, which Acton clearly opposed. He believes “Facebook isn’t the bad guy” and sees them more as a business people.

“At the end of the day, I sold my company. I sold my users’ privacy to a larger benefit. I made a choice and a compromise. And I live with that every day,” Acton told Forbes.

David Marcus, former head of messaging products and current lead of blockchain at Facebook, refuted Acton’s claims and wrote in a Facebook post that, “Mark personally shields founders from what typically frustrates them in larger companies, giving them unprecedented autonomy.” “I witnessed Mark defending it a number of internal meetings where there was push back — never for advertising or data collection reasons but for concerns about safety — and even in Board Meetings. Mark’s view was that WhatsApp was a private messaging app, and encryption helped ensure that people’s messages were truly private,” he added.

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Facebook is currently the most widely scrutinized public company in the world. Since it confirmed Russian interference on its platform to manipulate US Presidential elections in 2016, it is facing increased threat of regulation around the world. Recently, it was forced to change its privacy policy in order to incorporate Europe’s General Data Protection Regulation (GDPR).

However, the accounts of Instagram and WhatsApp co-founders raises questions around Facebook’s practice, especially one around pushing more advertisements and opening the platform to businesses. The critics question if such a practice would loosen the security aspect of these platforms. It is not clear whether Zuckerberg himself will comment on these allegations but for now, Facebook remains the undisputed king of social media platforms.